This invention relates to an applicator for applying two or more tapes to a moving web and, more particularly, to tape tabs which are used on diapers and incontinent pads.
Disposable articles such as incontinent pads, surgical dressings, baby diapers, and the like, are frequently held in place during use by tape tabs which are attached after the product is fitted snugly to the user's body. Illustrative is U.S. Pat. No. 2,990,081 which describes a device for intermittently withdrawing a length of tape from a supply roll, wrapping this around an arcuate portion of a backing roll, cutting segments therefrom, and advancing the cut segment such that it is applied to the product at the same speed as product movement. Patent '081 shows the basic theory used in all of the prior art devices whereby a portion of the outside surface of an anvil roll is in close proximity to a web substrate passing between the anvil roll and a backup roll.
Normally the non-sticky portion of the tape is entrained around this moving surface, and slips thereon (because it is still connected to the supply roll) until a cutoff knife roll coacts with the anvil to sever that portion which has advanced beyond the point at which cutoff occurs. Between the supply roll and entrainment around the anvil roll, the tape (usually with a removable release strip adhered to the sticky surface) passes through the nip of a feed roll pair which advances the tape and release strip at a speed substantially less than the speed of the product to which it will be attached. In effect, each of the prior art devices feeds combined strips of tape and release at a substantially uniform rate of feed, and after minor portions of the tape have been cut by coaction of the anvil and cutoff roll, they are held against the surface of the anvil roll by vacuum and are subsequently transported and transferred to the substrate medium such as a diaper, incontinent pad, etc.
These known devices essentially feed tape and release strip on the basis of one per machine revolution. It is also known that prior art devices apply individual tape tabs with release strips at equally spaced intervals onto the moving web or product. These devices have been frequently used and are quite acceptable even at high speeds when applying single tape tabs to articles such as disposable diapers. Also, in practice, two side-by-side tape applying means are used such that each side of the diaper receives one tape.
In the past few years, a number of product improvements have made disposable diapers and pads much more comfortable as well as more functional, and these improvements have generally allowed upsizing of disposable diapers so they can be used for adults.
By using two of the tape applying devices described above and further in U.S. Pat. Nos. 3,728,191, 3,960,646 and 4,001,072, two or more tapes with release strips can be applied to each incontinent pad or adult diapers, and by phasing each of the units differently, tape width (measured in the MD) and the distance between tapes can be altered to suit. However, the known units cannot apply two or more tapes to a single pad or diaper, nor do they have the ability to apply two tapes with spacing different from two other tapes in a series.
This invention is directed toward tape applicators that can apply two or more tapes per diaper to a continuously moving web of connected diapers such that spacing between consecutive pairs is different. In the particular embodiment disclosed, the invention includes an anvil roll constructed with a plurality of anvils and blades such that three tape tabs with release backing can be placed on each side of three different sizes of pads. In effect, a single device is capable of attaching three tapes to each side of a diaper being processed, and by changing over the position of cutoff blades and anvils, the same device can be used to place three tape tabs (with different spacing between tapes) on a second size pad. Still a third set of three tapes with a still different spacing therebetween can be placed on a third size of pad by making adjustments to the same device.